Benchmark: compound let assignment

Tests:

Compound let
for (let a = 0; a < 10000000; a++) { a += 1; }
Let
for (let a = 0; a < 10000000; a++) { a = a + 1; }
Compound var
for (var a = 0; a < 10000000; a++) { a += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Compound let
Let
Compound var

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's being tested in this specific benchmark.

**Benchmark Overview**

The provided JSON represents a microbenchmark that measures the performance of three different approaches to incrementing a variable in a `for` loop. The goal is to compare the execution times of these approaches across various browsers, devices, and operating systems.

**Benchmarked Approaches**

There are three test cases:

1. **Compound let**: `let a = 0; for (a++) { /* */ }`
2. **Let**: `let a = 0; for (a += 1) { /* */ }`
3. **Compound var**: `var a = 0; for (a += 1) { /* */ }`

**Comparison of Approaches**

Each approach has its pros and cons:

*   **Compound let**: This approach increments the variable in a single statement, which can lead to better compiler optimization. However, it may not be supported by older browsers or versions.
*   **Let**: This is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). It's a good choice when you need to declare variables in multiple places within the same scope. However, some older browsers might not support this syntax.
*   **Compound var**: This approach increments the variable in two separate statements, which can lead to slower execution times due to the overhead of re-declaration.

**Library and Special Features**

There are no libraries mentioned in the provided benchmark definition or test cases. However, it's worth noting that some browsers may optimize JavaScript code using Just-In-Time (JIT) compilation, which can affect the performance of these microbenchmarks.

The **let** keyword is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). It allows for variable declarations outside of function bodies and is a good alternative to the traditional `var` declaration. This feature provides better scoping and re-declaration behavior compared to traditional `var`.

**Other Considerations**

When writing microbenchmarks, it's essential to consider factors like:

*   **Browser support**: Make sure your benchmark supports a wide range of browsers and versions.
*   **Device platform**: Test your benchmark on various devices (desktop, mobile) to ensure consistent results.
*   **Operating system**: Include multiple operating systems in your test suite for more accurate comparisons.

**Alternatives**

Other alternatives for writing microbenchmarks include:

*   **Benchmark.js**: A popular benchmarking library that supports a wide range of browsers and platforms.
*   **Benchpress**: Another well-known benchmarking library that's easy to use and provides detailed results.
*   **Snyk**: A security-focused benchmarking platform that also provides performance testing capabilities.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36

Browser/OS: Chrome 101 on Mac OS X 10.14.6

View result in a separate tab

Test name	Executions per second
Compound let	190.9 Ops/sec
Let	193.3 Ops/sec
Compound var	192.7 Ops/sec

Related benchmarks:

compound let assignment (version: 0)

Comparing performance of: Compound let vs Let vs Compound var

Created: 7 years ago by: Guest

Jump to the latest result

Compound let

Let

Compound var

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):